A smooth vector bundle $p:E rightarrow B$ is a submersion












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Prove that a smooth vector bundle $p:E rightarrow B$ is a submersion. With $B$ being a smooth $k$ dimensional manifold, and $E$ be a bundle of dimension $n$.




I would like to see how one prove this. Below is my attempt, I would be happy for some comments too.





My proof relies on Theorem 4.14, pg 83, of Lee's Manifold,




(Global rank theorem). Let $M$ and $N$ be smooth manifolds, and suppose $F:M rightarrow N$ be a smooth map of constant rank. If $F$ is surjective, then $F$ is a smooth submersion.




It suffices to show that $p$ has constant rank. But with a local trivialization of $E$, over local chart $U$ of $B$, we know that $p$ has the coordinate representation,
$$ (x^1,ldots, x^k, x^{k+1}, ldots, x^{k+n}) rightarrow (x^1, ldots, x^k) $$
The Jacobian matrix has rank $k$.













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    $begingroup$



    Prove that a smooth vector bundle $p:E rightarrow B$ is a submersion. With $B$ being a smooth $k$ dimensional manifold, and $E$ be a bundle of dimension $n$.




    I would like to see how one prove this. Below is my attempt, I would be happy for some comments too.





    My proof relies on Theorem 4.14, pg 83, of Lee's Manifold,




    (Global rank theorem). Let $M$ and $N$ be smooth manifolds, and suppose $F:M rightarrow N$ be a smooth map of constant rank. If $F$ is surjective, then $F$ is a smooth submersion.




    It suffices to show that $p$ has constant rank. But with a local trivialization of $E$, over local chart $U$ of $B$, we know that $p$ has the coordinate representation,
    $$ (x^1,ldots, x^k, x^{k+1}, ldots, x^{k+n}) rightarrow (x^1, ldots, x^k) $$
    The Jacobian matrix has rank $k$.













    share|cite|improve this question









    $endgroup$















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      1








      1





      $begingroup$



      Prove that a smooth vector bundle $p:E rightarrow B$ is a submersion. With $B$ being a smooth $k$ dimensional manifold, and $E$ be a bundle of dimension $n$.




      I would like to see how one prove this. Below is my attempt, I would be happy for some comments too.





      My proof relies on Theorem 4.14, pg 83, of Lee's Manifold,




      (Global rank theorem). Let $M$ and $N$ be smooth manifolds, and suppose $F:M rightarrow N$ be a smooth map of constant rank. If $F$ is surjective, then $F$ is a smooth submersion.




      It suffices to show that $p$ has constant rank. But with a local trivialization of $E$, over local chart $U$ of $B$, we know that $p$ has the coordinate representation,
      $$ (x^1,ldots, x^k, x^{k+1}, ldots, x^{k+n}) rightarrow (x^1, ldots, x^k) $$
      The Jacobian matrix has rank $k$.













      share|cite|improve this question









      $endgroup$





      Prove that a smooth vector bundle $p:E rightarrow B$ is a submersion. With $B$ being a smooth $k$ dimensional manifold, and $E$ be a bundle of dimension $n$.




      I would like to see how one prove this. Below is my attempt, I would be happy for some comments too.





      My proof relies on Theorem 4.14, pg 83, of Lee's Manifold,




      (Global rank theorem). Let $M$ and $N$ be smooth manifolds, and suppose $F:M rightarrow N$ be a smooth map of constant rank. If $F$ is surjective, then $F$ is a smooth submersion.




      It suffices to show that $p$ has constant rank. But with a local trivialization of $E$, over local chart $U$ of $B$, we know that $p$ has the coordinate representation,
      $$ (x^1,ldots, x^k, x^{k+1}, ldots, x^{k+n}) rightarrow (x^1, ldots, x^k) $$
      The Jacobian matrix has rank $k$.










      differential-geometry differential-topology vector-bundles






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      asked Jan 2 at 2:06









      CL.CL.

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          Your proof is fine but kind of silly. You have computed that the differential has rank $k=dim B$ at every point, which is the definition of what it means for $p$ to be a submersion. There's no need to go through the theorem you mentioned.






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          • $begingroup$
            Oh yes, that is silly...
            $endgroup$
            – CL.
            Jan 2 at 2:58











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          1 Answer
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          $begingroup$

          Your proof is fine but kind of silly. You have computed that the differential has rank $k=dim B$ at every point, which is the definition of what it means for $p$ to be a submersion. There's no need to go through the theorem you mentioned.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Oh yes, that is silly...
            $endgroup$
            – CL.
            Jan 2 at 2:58
















          2












          $begingroup$

          Your proof is fine but kind of silly. You have computed that the differential has rank $k=dim B$ at every point, which is the definition of what it means for $p$ to be a submersion. There's no need to go through the theorem you mentioned.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Oh yes, that is silly...
            $endgroup$
            – CL.
            Jan 2 at 2:58














          2












          2








          2





          $begingroup$

          Your proof is fine but kind of silly. You have computed that the differential has rank $k=dim B$ at every point, which is the definition of what it means for $p$ to be a submersion. There's no need to go through the theorem you mentioned.






          share|cite|improve this answer









          $endgroup$



          Your proof is fine but kind of silly. You have computed that the differential has rank $k=dim B$ at every point, which is the definition of what it means for $p$ to be a submersion. There's no need to go through the theorem you mentioned.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 2 at 2:57









          Eric WofseyEric Wofsey

          188k14216346




          188k14216346












          • $begingroup$
            Oh yes, that is silly...
            $endgroup$
            – CL.
            Jan 2 at 2:58


















          • $begingroup$
            Oh yes, that is silly...
            $endgroup$
            – CL.
            Jan 2 at 2:58
















          $begingroup$
          Oh yes, that is silly...
          $endgroup$
          – CL.
          Jan 2 at 2:58




          $begingroup$
          Oh yes, that is silly...
          $endgroup$
          – CL.
          Jan 2 at 2:58


















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